Cellular Respiration Flashcards
glycolysis, krebs, anaerobic pathways
what happens if we dont have o2 during cell respiration?
no final e acceptor in the etc –> etc will eventually shut down (aerobic respirtaion) –> NADH cannot be oxidized –> no NAD+ for glycolysis –> cell respiration SHUTS down
what is the purpose of fermentation
keep glycolysis going without o2 by allowing e- to leave NADH to create NAD+ that will then oxidize G3P in glycolysis
lactic acid fermentation
reduce PYRUVATE by taking e- from NADH
- creates LACTIC ACID and NAD+
what does build up of lactic acid cause
- blood pH drops (co2 isn’t leaving (decarboxylation never occurs))
- ATP deficit: burning/cramping of overworked muscles
- Rigor mortis in dead tissue due to denaturation of proteins from lactic acid buildup
where is lactic acid flushed out to
flushed out of muscle into blood where its converted into pyruvate in the liver (cori cycle)
how is yogurt produced anaerobically
anaerobic bacteria produces lactic acid that denatures the protein in the milk after breaking the lactose down into glucose and galactose
which creatures use lactic acid fermentation
humans and mammals
why dont animals preform ethanol fermentation
they would get drunk
how does yeast use anaerobic pathways
yeast removes the COOH from pyruvate cresting acetaldehyde and then oxidizes NADH producing ethenol
- COOH exits as CO2
- this is the bubbles in bread
ethanol fermentation
- done by several species of bacteria/yeast
- PYRUVATE decarboxylates and becomes ACETYLADEHYDE
- reducing ACETYLADEHYDE results in ETHANOL and NAD+
why do lipids have more energy than carbs
lipids have many fatty acids that break down into acetyl-coA (used in krebs)
how do we get ATP from proteins
hydrolysis of peptide bond -> one a.a is cleaved off -> deamination (removing nh2) -> alpha-ketoacids produced –> enter krebs at various points depending on r-group
What is glycolysis
turning 6C sugar into two 3C sugars
(glucose —> pyruvate)
how many steps are in glycolysis
10, split into 2
steps 1-5: energy investment
steps 6-10: energy harvest
where does glycolysis take place
cytosol in ALL cells
what is step 1 of glycolysis
comitting glucose
- by attaching a PO4 from ATP, glucose is prevented from diffusing out
C6H11O6 + ATP —> G6P + ADP
what does G6P stand for
Glucose-6-Phosphate
step 2 glycolysis
G6P –> F6P
- isomers of each other
- aldose –> ketose
- if fructose directly consumed, step 1 is skipped and it enters glycolysis here
what does F6P stand for
Fructose 6-phosphateq
step 3 glycolysis
F6P + ATP –> F-1, 6- BP
- adding -PO4 to F6P
F-1, 6-BP
Fructose-1,6-bisphosphate
step 4 glycolysis
F-1, 6-BP –> G3P + DHAP
- 6C –> 3C + 3C
- DHAP cannot be used
G3P
Glyceraldehyde 3-phosphate
step 5 glycolysis
DHAP –> G3P
- isomers
- turning into something usable
- now we have TWO G3P, everything following will happen TWICE (products DOUBLE)
summarize the events that occur in energy investment
- 2 ATP used
- 1 ADP made
- 2 G3P made
step 6 glycolysis
G3P + PO4 + NAD+ –> 1,3 - BPG + NADH
- oxidizing G3P, moving the electron to NAD+, becoming NADH
- adding-PO4 to G3P
1,3 - BPG stands for…
1,3-Bisphosphoglycerate
step 7 glycolysis
1,3 - BPG + ADP –> 3 - PG
- substrate level phosphorylation
step 8/9 glycolysis
- 3- PG –> 2-PG
- 2-PG –> PEP
- moving PO4 over
- phosphorylation
3-PG stands for….
3-Phosphoglyceric acid
2-PG stands for..
2-Phosphoglyceric acid
PEP stands for…
Phosphoenolpyruvate
step 10 glycolysis
PEP + ADP –> ATP + Pyruvate
what are the results of energy harvest
- 2 NADH made
- 4 ATP made
- 3 ADP used
- 2 Pyruvate
what are the results of GLYCOLYSIS
- NET gain of 2 ATP
- net loss of 3 ADP
- 2 Pyruvate made
- 2 NADH made
where does krebs cycle take place
matrix
where is the matrix located
the space inside the inner membrane of the mitochondria
Pyruvate Oxidation
- occurs from cytosol to matrix
- pyruvate goes through decarboxylation (loses a CO2)
- pyruvate oxidized = NAD+ reduced = NADH
- CoEnzyme A added to pyruvate to lead into matrix
- 3C –> 2C
- becomes Acetyl-CoA
step 1 krebs
Acetyl-CoA adds its 2C to OXALOACETATE (4C) creating CITRATE (6C)
step 2 krebs
- ACONITATE made as a short-term intermediate as H2O shuffles around
CITRATE (6C) –> ISOCITRATE (6C) thru the removal and addition of H2O
step 3 krebs
oxidation and de-carboxylation
- ISOCITRATE is oxidized =NAD+ reduced –> NADH
- carboxyl group and exits as CO2
- 6C (ISOCITRATE ) –> 5C (ALPHA-KETOGLUTARATE)
step 4 krebs
5C (ALPHA-KETOGLUTARATE) –> 4C (SUCCINYL-COA)
- ALPHA-KETOGLUTARATE is decarboxylated, releasing CO2
- also oxidized = NAD+ reduced = NADH created
- coA added again
step 5 krebs
4C (SUCCINYL-COA) –> 4C (SUCCINATE)
- CoA replaced by -PO4
- PO4 passed to GDP –> GTP –> ATP
step 6 krebs
oxidation
- SUCCINATE (4C) is OXIDIZED = FAD+ reduced = FADH2 created
- 4C (SUCCINATE) –> 4C (FUMERATE)
step 7 krebs
FUMERATE (4C) –> MALATE (4C)
- water added
step 8
oxidation
- MALATE is oxidized = NAD+ reduced = NADH formed
- MALATE becomes OXALOACETATE which can regenerate krebs cycle
what would happen if oxaloacetate didnt regenerate in step 8?
- krebs cycle would eventually stop because you need oxaloacetate for acetyl-coA to attach to and begin the process
- when krebs eventually stops, cell can no longer rely on aerobic respiration to make ATP and would have to go to anaerobic
summarize the end results of krebs for each pyruvate
- 4 NADH made
- 1 FADH2 made
- 1 ATP
- 3 CO2
summarize the end results of krebs for each glucose
- 8 NADH made
- 2 FADH2 made
- 2 ATP
- 6 CO2
